Metastatic melanoma has very limited treatment options. However, advances in adoptive cell transfer (ACT) therapy and the development of clinically effective specific inhibitors for BRAF^^[unreadable][unreadable]^ oncogenic mutations are providing novel effective therapies for this disease. Over the past 5 years of ICMIC funding we have been testing both the immunotherapy and kinase inhibition approaches in preclinical models and in patients. Molecular imaging technologies have been critical, in both the preclinical mouse model studies and in the clinical investigations, in investigating and understanding the mechanisms of action of these new treatment strategies. For the next 5 years we propose to harnesses the benefits of molecular imaging to guide and evaluate novel therapeutic strategies for patients with metastatic melanoma. Our proposal has two dominant specific aims: Specific Aim 1. Imaging TCR Engineering Adoptive Cell Transfer Therapy in Humans. We hypothesize that the combined use of nucleoside-based PET probes ([^^FJFLT and [ FjFAC) and PET reporter gene expression (HSV1-sr39tk imaged by [''^FjFHBG) will allow us to determine how best to define and implement ACT therapy based on T cell receptor (TCR) genetically redirected lymphocytes. The combination of small molecule-based PET tracers and PET reporter genes will allow us to determine, by non-invasive monitoring, how TCR transgenic cells adoptively transferred to patients with metastatic melanoma provide immune reconstitution and efficient tumor targeting. Specific Aim 2. Imaging Combined Therapy with Oncogenic BRAF[V6ooE) Inhibition and Immunotherapy. We hypothesize that the benefits of long term tumor responses with immunotherapy can be merged with the benefits of high frequency tumor responses with targeted small molecule oncogene inhibition. This approach will include the combination of TCR transgenic ACT and the specific BRAF inhibitor PLX4032 in HLA-A2.1 positive patients with BRAF(V600E) mutated melanoma. We will test, in murine models we are developing, if a combination of PET probes will allow the simultaneous study of immune activation ( [18] FJFAC) and tumor responses ([ [18] FjFDG). When properly evolved, we will take this combined therapy/combined imaging approach to the clinic.